Quote:
Originally Posted by Ryderscope
Hi Greg, just a quick observation on the polar alignment requirement. It is really going to depend on what focal length(s) you want to settle on. In my case I’m sticking to my Samyang 14mm f2.8 lens with the Canon 60Da resulting in a very wide field. Obviously this is a lot more forgiving on polar alignment accuracy than trying to image with a 200mm lens. I find that with the 14mm lens on board I achieve a satisfactory polar alignment by using a digital inclinometer to set the altitude and then a magnetic compass to align with true south. My mount is the Skywatcher Star Adventurer and the tracking is sufficiently accurate in this configuration to produce acceptable subs. I may apply a light touch of BlurXterminator in Pixinsight in post processing to tidy up the stars a little.
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I currently use a Fornax Lighttrack 11 portable on a carbon fibre tripod which is basically a high end unit with super low PE of less than 2 arc seconds.
I use a Vixen polar scope which is quite good but I have to use a Skywatcher illuminator which is a bit clumsy. The latest Vixen polar scope has a built in illuminator.
I have aligned it like that using an app which gives the compas direction and also an app for digital inclinometer. Yes this gives round stars at 30 seconds with a 14mm lens. 60 seconds starts to show elongation.
I practised finding the Octans Trapezium last time I used it and got to the point where I could find the trap 3 times out of 3 hand holding the polar scope and pointing to where I thought it would be by orienting off the SMC and the Pointers of the Southern Cross.
Then I got 180 second images with round stars. But I would like longer and I have a nice Samyang 135/F2 lens I would like to use and it's more demanding.
I have a Polemaster but found you virtually have to be polar aligned for it to show the Trap so I failed using that and trying a few times. Perhaps I get it closer using the polar scope and then polish it off using the Polemaster.
IOptron Skyguider Pro has a built in ipolar camera and an app for your phone. That sounds more what I need. It also can be autoguided.
I can also use a CEM70 to do lens imaging whilst my larger scopes are imaging, so a few options there. The CEM70 has ipolar so I'll see how good that is and if it's good it would make the iOptron the preferred option.
There are a ouple of high tech Japanese units. One is from Unitec and its called SWAT. Comes in 3 sizes, 200, 300 and 350. The 300 and 350 can have factory built in PEC.
But with the various accessories you would need to use one the cost is up around AUD$2500. PE after factory PEC is under 3 arc secs.
There is another Japanese made unit called Toast. It's cheaper but has less acessories and no PEC.
Greg.
